Determination of the properties and identity of the Ca pump and Na pump of isolated transverse tubules. This will be done by observation of phosphoprotein formation in SDS gel electrophoresis. Elucidation of the protein constituents of the triad junction. We are currently obtaining evidence concerning which protein or proteins in the transverse tubules and terminal cisternae are involved in the reformation of the triad junction when the individual vesicles are incubated together. We will continue this work employing proteolytic enzymes selectively to extract protein fragments from the vesicles and will determine whether these fragments are able to participate in a rejoining reaction with isolated organelles.